How many carbons does alpha ketoglutarate have?
Alpha ketoglutarate(AKG) contains 5 carbon atoms. Its molecular formula is C₅H₆O₅, placing it firmly in the category of five-carbon dicarboxylic keto acids. This seemingly simple answer opens the door to a surprisingly rich story about cellular energy, amino acid metabolism, and the growing role of AKG as a high-value health supplement ingredient.
【English name】: Alpha-Ketoglutarate
【CAS No.】: 328-50-7
【Molecular Formula】: C5H6O5
【Active ingredients】: Alpha-Ketoglutarate
【Specification】: Alpha-Ketoglutarate 99%
【Appearance】: White to yellowish powder
Shelf Life: 2 years Minimum Order
Quantity: 1 kg
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Molecular Structure of Alpha Ketoglutarate: 5 Carbons, One Vital Molecule
Almost everyone who has attended any kind of biochemistry class, no matter how short, has heard of the Krebs cycle. At its core, it is alpha ketoglutarate, often called 2-oxoglutarate or alpha-ketoglutaric acid. Named for its peculiar chemical reactivity, the molecule features a unique five-carbon backbone with two carboxyl groups and one ketone group at the alpha position.
5 Carbon Atoms in Alpha Ketoglutarate Molecular Formula: C₅H₆O₅ | CAS No.: 328-50-7 | MW: 146.10 g/mol
How is it possible to reduce a chemical with six carbon atoms to five? The mitochondria hold the key. Isocitrate, a six-carbon intermediate, is oxidatively decarboxylated in the citric acid cycle's third stage. While producing a co-factor, NADH, one carbon is lost as carbon dioxide. Only alpha ketoglutarate remains. There are exactly five carbon atoms in it. One of the critical steps in cellular energy production, decarboxylation is by no means an accident.
At a Glance: Alpha Ketoglutarate Molecular Profile
IUPAC Name: 2-Oxopentanedioic acid
Synonyms: 2-Oxoglutaric acid, α-KG
Carbon Count: 5 carbons (C₅)
Oxygen Count: 5 oxygens (O₅)
Hydrogen Count: 6 hydrogens (H₆)
Functional Groups: 2 carboxyl, 1 ketone
Where Does the Carbon Count Come From?
Each of the five carbons in alpha ketoglutarate occupies a specific structural position. Carbon 1 forms the first carboxyl group (–COOH). Carbon 2 is the alpha carbon ,it carries the ketone group (C=O) that defines this compound's chemical identity. Carbons 3 and 4 form the methylene bridge connecting the two acid ends. Carbon 5 holds the second carboxyl group. This arrangement creates two acidic terminals separated by a short chain, making alpha ketoglutarate bifunctional. It can accept electrons on one side and donate protons on the other, a property that underlies its role in both energy metabolism and redox regulation.
Alpha Ketoglutarate in the Krebs Cycle: A Central Player in Energy Metabolism
The Krebs cycle, formally called the tricarboxylic acid (TCA) cycle, is the engine that drives aerobic respiration in virtually every living cell. Alpha ketoglutarate is one of its key intermediates. Understanding what it does inside this cycle reveals why formulators of health supplement ingredients prize it so highly.
Step-by-Step: AKG's Place in the TCA Cycle
1. Citrate → Isocitrate: The cycle begins with the condensation of acetyl-CoA and oxaloacetate to form the 6-carbon molecule citrate. Isomerization follows, yielding isocitrate.
2. Isocitrate → Alpha Ketoglutarate (AKG): Isocitrate dehydrogenase catalyzes this step. One CO₂ molecule is released, NADH is generated, and the 5-carbon AKG is formed. This is a pivotal energy-releasing step.
3. AKG → Succinyl-CoA: The alpha-ketoglutarate dehydrogenase complex converts AKG into the 4-carbon succinyl-CoA. A second CO₂ is released, and another NADH is produced. This reaction closely resembles pyruvate dehydrogenase in both structure and mechanism.
4. Continuation to Oxaloacetate: Succinyl-CoA proceeds through fumarate, malate, and finally regenerates oxaloacetate , completing the cycle and setting the stage for another turn.
With each complete cycle of the TCA cycle, three molecules of NADH, one of FADH₂, and one of GTP are produced. A second NADH is produced in this sequence when alpha ketoglutarate is converted to succinyl-CoA. The cycle decelerates in the absence of enough AKG. ATP synthesis decreases. Muscle fibres, enterocytes, immune cells, and other cells that rely on a high metabolic throughput are the first to notice the shortage.
AKG as a Nitrogen Scavenger
Alpha ketoglutarate is also an important nitrogen scavenger, in addition to energy. In transamination processes, AKG absorbs an amino group from amino acids like glutamate, transforming them into novel amino acids or eliminating superfluous nitrogen from the bloodstream. This transfer produces glutamate, which may subsequently enter the urea cycle to detoxify ammonia. This shuttle is important for muscle tissue particularly during heavy physical exercise when protein turnover is increased.
One review in Biomolecules & Therapeutics (2016) states that AKG "stimulates protein synthesis and inhibits protein degradation in muscles" by acting as a nitrogen scavenger and providing glutamate and glutamine. AKG is a molecule with more functions than most single metabolites because of its dual involvement in energy and nitrogen regulation.
Key Physiological Functions of Alpha Ketoglutarate
Scholars have gone far beyond painting it as just a link in the chain. With an ever-growing corpus of peer-reviewed research, this fascinating premium ingredient in health supplement formulations has been shown to have a variety of interesting purposes in the last decade.
Antioxidant Activity and ROS Scavenging
Direct reactions with hydrogen peroxide (H2O2) allow alpha-ketoglutarate to go through an oxidative decarboxylation process that does not include enzymes. Hydrogen peroxide (H2O2) interacts with the alpha carbon ketone group to produce carbon dioxide (CO2), water, and the corresponding carboxylic acid. The result? An oxygen species that is reactive and cannot be neutralised by an enzyme. Oxidative Medicine and Cellular Longevity released data confirming that AKG "scavenges H2O2 to alleviate oxidative stress via nonenzymatic oxidative decarboxylation" (Liu et al., 2018). When metabolic stress is present, this pathway may be very useful since it supplements the enzymatic antioxidant network.
Epigenetic Regulation
One of the most unexpected results concerns the participation of AKG in the cell nucleus. Part of the cellular AKG pool is used by the nucleus as a co-substrate for dioxygenase enzymes mediating DNA and histone demethylation. In simple terms, AKG controls which genes are turned on and off. In Biomedicines (2026) researchers identify AKG as a “signalling molecule that links mitochondrial function with epigenetic remodelling”. This finding takes AKG from a housekeeping molecule in metabolism to a genuinely fide regulator of gene expression.
Immune Modulation and Inflammatory Balance
AKG also affects the behaviour of immunological cells. It causes polarisation of macrophages into an anti-inflammatory phenotype and inhibits the NF-κB signalling pathway involved in chronic inflammatory responses. AKG suppresses production of pro-inflammatory cytokines, stimulates extracellular matrix formation and lowers cartilage degradation.” MDPI Biomedicines, 2026.“This is an interesting finding for formulators who are thinking about joint and recovery ingredients.
Skeletal Muscle Support and Protein Metabolism
Nutrients released a narrative evaluation of 112 peer-reviewed literature on AKG and skeletal muscle health in November 2024. By activating muscle satellite cells (MuSCs) and macrophage polarisation, the researchers discovered that AKG enhances muscle recovery. These processes are important in muscle regeneration and limit fibrosis. They also found that athletes who take an AKG supplement report "increased endurance, reduced fatigue and supported faster post-exercise recovery." The results could be connected to the fact that AKG has a five-carbon backbone and that its form has to fit into metabolic pathways so that it can make protein energy and maintain nitrogen equilibrium.
Alpha Ketoglutarate as a Health Supplement Ingredient: Industry Applications
The functional breadth stated above has made alpha ketoglutarate a sought after raw material in various industries. It’s not a completed consumer product. It is instead a high-purity active ingredient that formulators and product developers use to their own compositions. Buyers may take use of the variety of its applications to see where AKG fits into their unique product strategy.
Sports Nutrition and Performance Formulations
For quite some time now, AKG has been a mainstay of protein and amino acid based sports supplements - generally in the form of arginine alpha-ketoglutarate (AAKG) or ornithine alpha-ketoglutarate (OKG). The thought process is simple: When AKG is combined with certain amino acids, it is meant to promote nitrogen recycling, increase sustained energy output, and permit faster recovery time between training sessions. The WebMD ingredient description notes that AKG supplements are occasionally used to boost athletic performance or aid with wound healing.
Healthy Aging and Longevity Formulas
AKG has attracted considerable attention as a longevity-promoting compound after preclinical studies demonstrated lifespan extension in model organisms. AKG might perhaps influence ageing in humans and hence possibly lengthen health span and enhance healthy lifespan (ScienceDirect, 2021).“ Calcium alpha-ketoglutarate (Ca-AKG) has been particularly interesting for its potential to help with bone health and age-related physiological changes.
Nutraceuticals and Functional Food Ingredients
You may use AKG in capsules, tablets, and powder mixes since it is available in a GRAS-near profile and a clean white-to-yellow powder. Very compatible with a wide variety of co-ingredients, water-soluble, and stable under standard storage conditions. Incorporating it into vitamin, mineral, and amino acid complexes in nutritional supplements, functional foods, and beverages is a common practice among formulators. The AKG component from Rebecca Bio-Tech is 99% pure, allowing for accurate dosage in finished products.
Gastrointestinal Health Formulations
The gastrointestinal tract has a very high metabolic rate. The intestinal lining cells, known as enterocytes, depend heavily on glutamine for their survival. According to Rui et al. (Biomolecules & Therapeutics), AKG is "a central metabolic fuel for cells of the gastrointestinal tract" since it is a direct precursor of glutamine. Formulators who prioritise gut health and mucosal integrity are very aware of this.
Alpha Ketoglutarate Supplier: Rebecca Bio-Tech
Plant extracts, herbal active ingredient separation, and functional compounds of traditional Chinese herbal remedies are the specialities of Shaanxi Rebecca Bio-Tech Co., Ltd., a high-tech export-oriented firm. Our yearly production capacity exceeds 500 metric tonnes, thanks to our three specialist manufacturing lines. We service global markets for pharmaceuticals, health products, beverages, and cosmetics.
Our alpha ketoglutarate is manufactured to exacting standards. It is a focused, single-active ingredient , not a blend, which gives our B2B clients full control over dosing and formulation. With over 100 plant extract and active ingredient products on offer, Rebecca Bio-Tech brings both breadth and depth to ingredient sourcing partnerships.
Ready to explore alpha ketoglutarate for your next formulation? Contact our ingredient team today for product documentation, Certificate of Analysis, pricing, and sample requests.
Send an Inquiry: information@sxrebecca.com
FAQ
Q1: How many carbons does alpha ketoglutarate have?
A: Alpha ketoglutarate contains 5 carbon atoms. Its molecular formula is C₅H₆O₅, and it is formally named 2-oxopentanedioic acid. It is produced in the citric acid cycle when the 6-carbon compound isocitrate loses one carbon as CO₂ during oxidative decarboxylation.
Q2: What is the difference between alpha ketoglutarate and isocitrate?
A: Isocitrate is a 6-carbon intermediate earlier in the citric acid cycle. When isocitrate dehydrogenase acts on isocitrate, one carbon is shed as CO₂, and NADH is generated — leaving behind the 5-carbon alpha ketoglutarate. So alpha ketoglutarate is simply isocitrate minus one carbon, resulting from a decarboxylation and oxidation reaction.
Q3: Is alpha ketoglutarate the same as glutamate?
A: No, but they are closely related. Glutamate is an amino acid with 5 carbons and an amino group (–NH₂) at carbon 2. Alpha ketoglutarate also has 5 carbons, but instead of an amino group, it carries a ketone group (C=O) at carbon 2. In transamination reactions, glutamate can lose its amino group and become alpha ketoglutarate — and vice versa. They are interconverted constantly in cellular metabolism.
Q4: What purity grade of alpha ketoglutarate is used in health supplement ingredients?
A: High-quality suppliers typically offer alpha ketoglutarate at ≥99% purity (HPLC-verified), appearing as a white to yellowish crystalline powder. This level of purity supports precise dosing in capsules, powders, and functional food applications. Always request a Certificate of Analysis (CoA) from your supplier to confirm specifications before procurement.
Q5: What industries use alpha ketoglutarate as an ingredient?
A: Alpha ketoglutarate is used primarily in sports nutrition, healthy aging formulations, functional foods, beverages, and cosmetic ingredient systems. It is a B2B raw ingredient, not a finished consumer product. Manufacturers in the pharmaceutical excipient, nutraceutical, and health food industries source it from specialized plant-extract and biochemical producers such as Rebecca Bio-Tech.
References
1. Liu, S., He, L., & Yao, K. (2018). "The Antioxidative Function of Alpha-Ketoglutarate and Its Applications." Oxidative Medicine and Cellular Longevity, 2018, 3408467.
2. Rui, R., et al. (2016). "Alpha-Ketoglutarate: Physiological Functions and Applications." Biomolecules & Therapeutics, 24(1), 1–8.
3. Durá-Traverso, G., et al. (2024). "Impact of Alpha-Ketoglutarate on Skeletal Muscle Health and Exercise Performance: A Narrative Review." Nutrients, 16(23), 3968.
4. Harrison, A.P., et al. (2021). "Alpha-Ketoglutarate Dietary Supplementation to Improve Health in Humans." Current Opinion in Clinical Nutrition & Metabolic Care.
5. Singh, R., et al. (2026). "Alpha-Ketoglutarate: A Metabolic Regulator of Cellular Homeostasis and Pathophysiology." Biomedicines, 14(4), 836.
6. WebMD. (2024). Alpha-Ketoglutarate (AKG): Uses, Side Effects, Interactions, Pictures, Warnings & Dosing.
